Copper

Gallium

Germanium

Arsenide

Selenium

{title2=Br}
{title2=35}
{title2=4s2 4p5}
{wiki}


Bromine

Niobium

{title2=Ag}
{title2=47}
{title2=4d10 5s1}
{wiki}


Silver

Cadmium

{title2=Sn}
{title2=50}
{title2=Stannum}
{wiki}


{title2=Cs}
{title2=55}
{title2=$6s^1$}
{wiki}

= Cesium
{synonym}


Caesium

{title2=Ba}
{title2=56}
{title2=$6s^2$}
{wiki}


Barium

{title2=Yb}
{title2=60}
{title2=$4d^1$}
{wiki}

Not "Yt" because that is already "Yttrium". God.


Ytterbium

Gold

Lead

Bismuth

{title2=Po}
{title2=84}
{title2=July 1998}
{wiki}

Discovered by <Marie Curie>, published July 1999.


Polonium

{title2=Ra}
{title2=88}
{title2=December 1989}
{wiki}

Discovered by <Marie Curie> when she noticed that there was some yet unknown more radioactive element in their raw samples, after <uranium> and <polonium>, which she published 6 months prior, had already been separated. Published on December 1989 as: <Sur une nouvelle substance fortement radio-active, contenue dans la pechblende>{full}.

The <uranium 238 decay chain> is the main source of naturally occurring <radium>.

\Video[https://www.youtube.com/watch?v=wAZX8sWSCqs]
{title=The epic story of radium by Institut de Radioprotection et de Sûreté Nucléaire (2013)}


Ciro Santilli @cirosantilli 37

 Children: List of chemical elements